Add modifying operations

go.mod

@@ -1,3 +1,5 @@
 module modifier
 
 go 1.24.1
+
+require github.com/Knetic/govaluate v3.0.0+incompatible

go.sum

@@ -0,0 +1,2 @@
+github.com/Knetic/govaluate v3.0.0+incompatible h1:7o6+MAPhYTCF0+fdvoz1xDedhRb4f6s9Tn1Tt7/WTEg=
+github.com/Knetic/govaluate v3.0.0+incompatible/go.mod h1:r7JcOSlj0wfOMncg0iLm8Leh48TZaKVeNIfJntJ2wa0=

main.go

@@ -1,14 +1,21 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"io"
 	"log"
 	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/Knetic/govaluate"
 )
 
 var Error *log.Logger
 var Warning *log.Logger
+
 func init() {
 	log.SetFlags(log.Lmicroseconds | log.Lshortfile)
 	logger := io.MultiWriter(os.Stdout)
@@ -23,7 +30,67 @@ func init() {
 }
 
 func main() {
-	log.Println("Hello, World!")
+	flag.Parse()
-	Warning.Println("Hello, World!")
+	args := flag.Args()
-	Error.Println("Hello, World!")
+	if len(args) == 0 {
+		Error.Println("No files provided")
+		log.Printf("Usage: %s <field> <operation> <...files>", os.Args[0])
+		log.Printf("Example: %s go run . \"<ticksBetweenBursts>(\\d+)</ticksBetweenBursts>\" \"/10\" Vehicle_JLTV.xml", os.Args[0])
+		log.Printf("Note: Field must include valid regex with one capture group")
+		return
+	}
+	field := args[0]
+	operation := args[1]
+	files := args[2:]
+	if field == "" || operation == "" || len(files) == 0 {
+		Error.Println("Invalid arguments")
+		log.Printf("Usage: %s <field> <operation> <...files>", os.Args[0])
+		return
+	}
+	log.Printf("Field: %s", field)
+	log.Printf("Operation: %s", operation)
+	log.Printf("Processing files: %v", files)
+	fieldRegex, err := regexp.Compile(field)
+	if err != nil {
+		Error.Printf("Error compiling field regex: %v", err)
+		return
+	}
+
+	for _, file := range files {
+		log.Printf("Processing file: %s", file)
+		fullPath := filepath.Join(".", file)
+		content, err := os.ReadFile(fullPath)
+		if err != nil {
+			Error.Printf("Error reading file: %v", err)
+			continue
+		}
+		lines := strings.Split(string(content), "\n")
+		for i, line := range lines {
+			matches := fieldRegex.FindStringSubmatch(line)
+			if len(matches) > 1 {
+				log.Printf("Line: %s", line)
+				oldValue := matches[1]
+				expression, err := govaluate.NewEvaluableExpression(oldValue + operation)
+				if err != nil {
+					Error.Printf("Error creating expression: %v", err)
+					continue
+				}
+				parameters := map[string]interface{}{"oldValue": oldValue}
+				newValue, err := expression.Evaluate(parameters)
+				if err != nil {
+					Error.Printf("Error evaluating expression: %v", err)
+					continue
+				}
+				updatedLine := strings.Replace(line, oldValue, fmt.Sprintf("%v", newValue), 1)
+				log.Printf("Updated line: %s", updatedLine)
+				lines[i] = updatedLine
+			}
+		}
+		err = os.WriteFile(fullPath, []byte(strings.Join(lines, "\n")), 0644)
+		if err != nil {
+			Error.Printf("Error writing file: %v", err)
+			continue
+		}
+		log.Printf("File %s updated successfully", file)
+	}
 }